The present invention relates to electronic imaging systems and, more particularly, to an electronic imaging system permitting transmission and reception of image data via a universal serial bus.
Recently, a data signal transmitting and receiving means called universal serial bus (USB) has been proposed as the digital data transmitting and receiving means connecting a personal computer or the like and a peripheral unit. Such USB permits inter-connection of a plurality of CPU-incorporating units just like a so-called LAN network by using a host computer, which is a personal computer having USB control function.
In the mean time, electronic cameras for recording photographed images as digital data, find various data utilizing applications by connecting a personal computer or like processor to them. Furthermore, an electronic camera itself may be utilized as a terminal unit of a personal computer through connection to the USB. In this case, it is readily possible to permit image data obtained in photography in an electronic camera to be printed out in a printer or stored in various recording media under control of a personal computer as host CPU.
FIG. 9 is a view for describing an example of data utilizing application of the electronic camera connected to the USB with a personal computer connected thereto as a host. In the illustrated application, a digital electronic camera 101 is connected to an USB 102, which is controlled by a personal computer 100 serving as host CPU. A printer 103 and a recording medium 104 are further connected to the USB. In this system, the personal computer 100 outputs control signal by judging terminal units connected to the USB. Each terminal unit connected to the USB sends out the data or the like in synchronism to the control signal. In this way, the image data obtained in the electronic camera 101 may be printed in the printer 103 or recorded in the recording medium 104.
However, in the above system using the USB, each terminal unit connected to the USB should be controlled by the personal computer as host CPU. Therefore, in a case where only an electronic camera and a printer, for instance, are connected to the USB hub without use of any host computer, it is impossible to transmit or receive the data when it is sought to print out image data of the electronic camera.
The present invention has been made in view of the above problem, and it has an object of providing an electronic imaging system, which permits optimum processing in dependence on whether any other host data processing unit is connected to the USB.
According to an aspect of the present invention, there is provided an electronic imaging system capable of permitting communication with an external unit via a universal serial bus, comprising: a host control means for collectively controlling an external unit connected via the universal serial bus as a host; a host detecting means for detecting that an external unit constituting a host data processing unit to the universal serial bus; and a mode setting means for setting a host mode permitting the operation of the host control means when the host detecting means detects no host data processing unit and also setting a terminal mode permitting operation under control of a host data processing unit when the host detecting means detects the host data processing unit.
The electronic imaging system further comprises a display means for displaying the mode set by the mode setting means and also displaying the kind of an external unit controlled by the host control means when the host mode is set by the mode setting means.
The electronic imaging system further comprises a data converting means for converting image data to data capable of being printed out in a printer, data generated as a result of data conversion in the data converting means being outputted, when a printer is connected as an external unit in the host mode set by the mode setting means, as image data to the printer.
The electronic imaging system further comprises a data converting means for converting image data to data capable of being stored in a data storing unit, data generated as a result of data conversion in the data converting means being outputted, when a data storing unit is connected as an external unit in the host mode set by the mode setting means, as image data to the data storing unit.